Shock absorber and method for operating a shock absorber in particular for a bicycle

ABSTRACT

Shock absorber and method for operating a shock absorber for a bicycle wherein a relative motion of a first and a second component interconnected via a damper device is dampened. The damper device includes a controllable damping valve with a field generating device with which a field-sensitive medium can be influenced for influencing a damping force of the damper device by applying a field intensity of the field generating device. A parameter for the current relative speeds of the first and second components is obtained in real time. For damping, a current field intensity to be set is derived in real time by way of the parameter from a characteristic damper curve and the field intensity to be currently set is generated by the field generating device in real time for setting in real time a damping force which results from the predetermined characteristic damper curve at the parameter obtained.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional, under 35 U.S.C. §120, of copendingpatent application Ser. No. 13/927,874, filed Jun. 26, 2013; theapplication also claims the priority, under 35 U.S.C. §119, of Germanapplication DE 10 2012 012 532.1, filed Jun. 26, 2012; the priorapplications are herewith incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a shock absorber for an at leastpartially muscle-powered vehicle and in particular a bicycle. Thebicycle may be equipped with an auxiliary drive and in particular anelectric auxiliary drive.

Many different types of rear wheel dampers and suspension forks forbicycles have become known in the prior art. A shock absorber typicallycomprises a spring unit for cushioning any shocks occurring and adamping unit for damping the spring vibration. In the case of rear wheelshock absorbers the spring unit and the damping unit are as a ruleconfigured as an integral unit. In the case of suspension forks thedamping unit and the spring unit may be disposed separately.

Most dampers for bicycles are operated with oil as the damping fluid.For damping, the damping fluid is conveyed from a first damping chamberto a second damping chamber through a valve gate throttling the flow.The size of the valve gate aperture determines the damping strength. Anoptimal damping is dependent on a number of factors such as for examplethe rider's weight and in particular the terrain characteristics. It isdesirable to set the damping strength in relation to loads such thatweak shocks are dampened less than heavy shocks. For rides on a road, aforest path, or directly off-road, different damping settings aretherefore optimal.

For adjusting and influencing damping, magneto-rheological andelectro-rheological fluids have become known whose characteristics canbe influenced by way of applying a suitable magnetic or electric field.

Most magneto-rheological fluids consist of a suspension of smallparticles that polarize magnetically and which are finely dispersed in acarrier liquid such as oil. The polarizing particles which tend toconsist of a carbonyl ferrous powder have typical diameters betweenapproximately 0.1 and 50 micrometers, under the influence of a magneticfield forming chain-like structures capable of absorbing field-dependentshear stresses. This allows to change for example the flow resistance ofa valve in a way similar to viscosity changes. The process is fast andreversible such that the initial rheologic state will be reinstated asthe magnetic field is broken. Thus, magneto-rheological fluids aresuitable to be used in dampers of bicycles.

With DE 698 21 799 T2 a rear wheel shock absorber for bicycles hasbecome known which is dampened by means of a magneto-rheological fluid.One end of a damper chamber is provided, via a bore, with an outwardlyconnection to an external damping valve which is connected with anexternal unit disposed in parallel in which the second damper chamber isaccommodated. The damping valve is provided with a permanent magnetwhose position relative to the flow gap can be changed for adjusting themagnetic field strength in the flow gap. The disadvantage of such asystem is the complex structure requiring a damper chamber disposedseparately and in parallel which increases the construction and themounting steps and the weight of the rear wheel shock absorber.

A general drawback of shock absorbers operating with electro-rheologicalor magneto-rheological fluids is that the damping of shocks requires tofirst overcome a breakaway force before a flow through themagneto-rheological damper valve occurs. The reason for this is forexample the comparatively stable interlinking between themagneto-rheological particles along the field lines. Flow through adamping duct is possible only as the breakaway force is overcome. Knownmagneto-rheological dampers provide for setting a specific, adjustabledamping force. The drawback of this is, however, poor responsivity sincethe shock absorber will not respond before the breakaway force has beenovercome. With a soft shock absorber setting the breakaway force isovercome relatively fast and with a hard shock absorber setting thebreakaway force is only overcome with large forces. In both cases,however, the shock absorber will not respond until the respectivebreakaway force is overcome.

EP 2 278 185 A1 discloses a magneto-rheological rear wheel shockabsorber for a bicycle in which the strength of the magnetic fieldacting in the damping duct is set mechanically through a rotary ring.Damping can be adjusted both in the compression stage and in the reboundstage. The shock absorber offers agreeable responsivity since anadjustable portion of the damping duct exposed to the magnetic fieldensures a zero passage in the force-velocity diagram. Another advantageof such a system is that operation does not require any electric energy.Flexible or electronic adjustment of changes to the dampercharacteristics is difficult though.

WO 2010/007433 A2 discloses a shock absorber for bicycles in whichdamping in the compression stage is influenced by a magneto-rheologicalvalve. An acceleration sensor detects the acceleration value atpredetermined time intervals, activating the electric coil for dampingthe flow through the damping valve if an acceleration value exceeds apredetermined threshold. This shock absorber and the method performedtherewith cause the damping of shocks and in what is called sway pedalstroke it prohibits the seesawing motion called “pedal bob” due to theperiodic damper compressions. Furthermore the known damper allows tocapture the acceleration values for specific periods to automaticallydetermine the type of the terrain in which the cyclist rides. Thequantity and magnitude of the acceleration values for example allows todetermine whether the rider travels on smooth tarmac or else throughrough terrain. The damping can be adapted according to the history dataso as to set a hard damping on a smooth road while soft damping ispreferred in rough terrain.

Such a damper is basically functional. There is, however, thedisadvantage that for riding on a smooth road the damping is set hardsuch that when crossing potholes or the like there is virtually nodamping and the impact is passed on virtually undampened. Although insway pedal strokes the shock absorber prevents the damper fromperiodically bobbing, shocks will not be dampened either. A zero passageof the force-velocity diagram is also absent with the damping activatedsince the breakaway force of the MRF particles must first be overcomebefore any damping occurs. Another drawback is that rides on roadsconsume much electric energy for setting the hard damping required. Thishas adverse effects on the operational range, or larger batteries oraccumulators must be employed which increases the weight. An increase ofweight is, however, not desired.

Some ideas have also been disclosed of employing GPS sensors or the liketo set electrically controlled shock absorbers dependent on theirpositions. A GPS signal allows to set the shock absorber for example tothe “road” setting and thus hard while the damper will be set softer forrides through rough terrain. The drawback of these systems is, however,that, the comparably high accuracy of GPS signals notwithstanding,specifically on farm ways, forest or walking paths it may make aconsiderable difference whether the bicycle travels farther to the rightor the left by 50 cm or only 10 cm or even all of 1 cm. Therefore,notwithstanding satellite-based positioning and suitable maps uploaded,the shock absorber settings may be unsuitable.

Some consideration has been given to recording the loads acting on ashock absorber for example when riding laps and setting the shockabsorber for riding the next lap according to the previously recordedvalues so as to provide favorable damping properties. The drawback ofthis is once again that the second lap will not involve precisely thesame way as does the first lap. A deviation of just one or a fewcentimeters may make a difference as to whether one rides over or arounda root. Moreover, minor lateral deviations may already suffice forcausing considerable changes in the ground such that even when data ofpreviously traveled laps are accessed, considerable deviations from theactual loads acting on the shock absorber may be present.

Basically, optical recognition systems for example for motor vehicleshave recently been disclosed by way of which near field recognition ofthe ground in front of the vehicle can be done. To this end, laserdiodes or the like capture by radar the terrain in front of the vehicleand the terrain in front of the vehicle is virtually capturedthree-dimensionally. This works for example for vehicles in early curverecognition where accordingly the different vehicle shock absorbers arepreset differently so as to obtain optimal riding conditions in thecurve. It may remain open whether these kinds of systems might alreadytoday be conceivable to be employed on a bicycle and for recognizing theground in downhill rides, since at any rate this kind of recognitionrequires quite considerable computing capacity and computing time. Infact, these kinds of ground recognition systems only ever allow toachieve digital shifting. The damper is either set hard or else soft bythe magnetic field. When a magnetic field is acting, the shock absorberdoes no longer have a zero passage in the force-velocity diagram suchthat responsivity is poorer. Although applying a highly inhomogeneousmagnetic field to the damping duct as in EP 2 278 185 A1 may provideagreeable responsivity, achieving variations of these inhomogeneousmagnetic fields is not simple.

In the case of conventional shock absorbers, however, a zero passage inthe force-velocity diagram is also present when the shock absorber showsa harder basic setting, which will always result in agreeableresponsivity. Only activating a lockout mode will block a conventionalshock absorber but in this way the shock absorber is virtuallyintentionally deactivated.

BRIEF SUMMARY OF THE INVENTION

It is therefore the object of the present invention to provide a shockabsorber and a method for operating a shock absorber by means of whichto allow flexible control and by means of which soft responsivity isenabled with different loads.

This object is solved by a method for operating a shock absorber havingthe features of claim 1 and by a shock absorber for an at leastpartially muscle-powered bicycle having the features of claim 21.Preferred specific embodiments of the invention are the subjects of thesubclaims. Further advantages and features of the invention can be takenfrom the general description and the description of the exemplaryembodiment.

The method according to the invention serves for operating at least oneshock absorber for an at least partially muscle-powered vehicle and inparticular a bicycle wherein at least a relative motion of first andsecond components interconnected via a damper device is dampened. Thedamper device comprises at least one controllable damping valve with atleast one field generating device and in particular an electric coildevice with which to act on a field-sensitive medium for acting on adamping force of the damping device by generating a field intensity ofthe field generating device and in particular by generating a fieldintensity by applying an electric current intensity to at least oneelectric coil device. In particular for event recognition at least oneparameter for the current relative speeds of the first and secondcomponents to one another are periodically obtained in real time. Bymeans of the parameter a measure for a field intensity to be set fordamping is derived in real time from a characteristic damper curve. Thefield generating device serves to generate in real time the fieldintensity to be currently set for setting in real time a damping forcewhich results from the predetermined characteristic damper curve at theparameter obtained.

In this document, “current” standing alone is understood to mean“present” or “presently” whereas “electric current” is being used for“electric energy”.

The method according to the invention has many advantages. Aconsiderable advantage of the method according to the invention consistsin that at least one parameter for a current relative speed of the firstand second components to one another is obtained. By means of acharacteristic damper curve a field intensity to be currently set isderived and set such that the damping force associated with the relativespeed is on the whole adjusted in real time at the damper device. Theterm “in real time” means that the entire system fulfills the real-timerequirements occurring. It follows that the system is sufficiently fastin capturing and evaluating data and sufficiently fast in forwarding asuitable field intensity to the field generating unit and thus forcechanges occur fast enough for adequate response to the respective event.

In this the current relative speed is determined and not for example anaverage value over one minute or more for performing automatic terrainrecognition. Presently a parameter for the current relative speed at thetime is obtained. The path of the relative speed over time issufficiently highly resolved during one single shock so as to provideadequate damping force at every point in time of the shock.

A considerable advantage over the prior art is the fact that with theinvention any occurring event such as a shock or seesawing motion or anyother disturbance or the like is recognized, and response takes place,in real time.

This means that in normal state without any events of e.g. disturbances,there is for example no field applied to the field generating devicesince in the absence of disturbances there is also an absence ofrelative speed between the first and second components. From this itimmediately follows that electric energy will be required for operatingthe damping valve at the most in the case of events in the form ofshocks or vibrations or the like.

Quite specifically this means that for example in riding in sway pedalstroke a field will only be applied in those brief points in time wherethere is relative motion such that the coil as the field generatingdevice may remain currentless at least ca. 50% of the time which allowsconsiderable saving of electric energy. The low feed of electric energyalso reduces the heat input.

In rides through rough terrain the coil will also be energized only if acorresponding current relative speed is present. In fact, damping doesnot even require electric energy in every event since the damper dampsshocks without requiring electricity by means of the basic dampinginherent to the shock absorber. Electric energy needs to be used onlywhen a higher damping force is required.

The characteristic damper curve stored for example in a (data) memory ofthe damper device defines a dependence of the damping force from thespeed of the two components relative to one another. The damping forceresults from applying a suitable field intensity with the fieldgenerating device such that the characteristic damper curve alsodetermines the dependence of the field intensity on the relative speed.The field intensity in turn results from the electric current intensitywhich is applied to the electric coil device as the field generatingdevice. Thus the characteristic damper curve also defines the inparticular non-linear conjunction between the relative speed and theelectric current intensity of the coil device.

Preferably the method is carried out with a shock absorber that isdampened via a magneto-rheological fluid. Preferably at least oneelectric coil device is employed as the field generating device.

In another configuration of the invention the method according to theinvention serves for operating at least one shock absorber for an atleast partially muscle-powered vehicle and in particular a bicyclewherein at least a relative motion of first and second componentsinterconnected via a damper device is dampened. The damper devicecomprises at least one controllable damping valve with at least onefield generating device and in particular an electric coil device withwhich to act on a field-sensitive medium for acting on a damping forceof the damping device by generating a field intensity of the fieldgenerating device and in particular by generating a field intensity byapplying an electric current intensity to at least one electric coildevice. A control device for controlling is provided. A control cycle isrun through under periodical control. At least one current parameter forthe current relative speed of the first and second components relativeto one another is periodically obtained in the control cycle. By meansof the current parameter a current electric current intensity of thefield generating device is derived from a predetermined characteristicdamper curve in the control cycle. Thereafter the current electriccurrent intensity is applied on the field generating device in thecontrol cycle. In this way a damping force is set in real time duringpassing the control cycle, ensuing from the predetermined characteristicdamper curve at the obtained current parameter.

However, the embodiments of shock absorbers described in thisapplication may basically be equipped with electro-rheological fluids asfield-sensitive fluids. Correspondingly an electric field is applied inthese shock absorbers.

A characteristic damper curve in the sense of the present applicationmay be understood to mean a functional relationship which links therelative speed or the parameter with a damping force via a calculationrule. A characteristic damper curve is also understood to mean a mapdiagram which can be interrogated. Direct access to the control pointsprovided is possible or a suitable damping force is derived from a givenparameter using an interpolation or extrapolation method. Accordinglythe damping force can be linked with a field intensity to be generatedand the field intensity, with an electric current intensity to be set.

The first and second components may be any desired component of theshock absorber or for example of the bicycle at which the shock absorberis mounted. Thus the components may be opposite damper ends. It is alsopossible to understand the first and second components to be connectionelements or for example the stanchion (inner) tube and the slider(outer) tube of a suspension fork.

Simply put, the method for operating a shock absorber with which arelative motion of first and second interconnected (vehicle) componentsis captured by way of a damper device and with which, in dependence onan obtained dimension of the current relative motion, a field generatingdevice is set according to a predetermined characteristic damper curveor field curve.

The current speed of the relative motion between the first and secondcomponents to one another is periodically obtained and in dependence onthe dimension of the current speed of the relative motion the currentfield of the field generating device is set corresponding to apredetermined field curve or characteristic damper curve. In simplecases, given regular or substantially regular time intervals betweenmeasurements, a parameter for the current relative speed will directlyresult from the captured relative motion.

Unlike the prior art a characteristic damper curve is not mechanicallyspecified but the characteristic damper curve is dynamically generated.A specified characteristic damper curve is retraced at any time asneeded by way of setting the corresponding field intensities or electriccurrent intensities. This means that firstly, a characteristic dampercurve is specified or selected. Thereafter the damping force pertainingto every relative speed occurring is obtained and also set by way ofsetting a corresponding electric current intensity. This happens fastenough for the system to operate in real time. Response to any and allevents and shocks occurring is fast enough for the shock absorber tobehave as if the specified characteristic damper curve in the shockabsorber is realized mechanically. The difference to a purelymechanically structured shock absorber consists in the option to specifyand select any characteristic damper curve desired. Mechanicalmodifications to the shock absorber settings are not necessary. It iseven possible to set two successive characteristic damper curves therealization of which would not be possible in conventional, purelymechanically adjusted shock absorbers for example if they involveincompatible mechanical properties. In this way enormous flexibility isachieved.

It is particularly preferred for the damping force to be increased withincreasing relative speed. It is also particularly preferred for thedamping force to increase with increasing field intensity and inparticular with increasing electric current intensity of the fieldgenerating device. Such a configuration allows a particularlyenergy-saving operation since a field from the field generating deviceis required only when a suitable damping force is needed. In normalstate, with no relative motion between the first and second components,field intensity and thus electric energy is consequently not needed.This allows energy-saving operation for example in rides on a smoothroad at a high pedaling frequency since these conditions will as a rulenot involve any or hardly any shocks on the shock absorber. Seesawingmotions will also not at all or hardly occur with a high pedalingfrequency.

Particularly preferably the characteristic damper curve, in the regionof low positive and/or negative relative speeds, shows a path which canbe approximated or described by a straight line with a predeterminedlow-speed gradient. Particularly preferably the characteristic dampercurve is substantially configured linearly in the region of low positiveand/or negative relative speeds. The gradients in the regions of thepositive and negative relative speeds may differ.

It is also particularly preferred for the characteristic damper curve tobe approximated or described by a straight line with a predeterminedhigh-speed gradient in the region of high positive and/or negativerelative speeds. Preferably the characteristic damper curve is at leastsubstantially linear in the region of high relative speeds. Again thegradients for the rebound and compression stages may differ.

In medium regions of positive and/or negative relative speeds at leastone linear or curved transition region may be provided in which anon-linear path of the damping force or field intensity over therelative speed is provided.

In any case the characteristic damper curve serves as the basis forcontrolling the shock absorber. After capturing a parameter or thecurrent relative speed itself the parameter or the corresponding currentspeed obtains, by means of the provided characteristic damper curve, apertaining damping force and thus a pertaining current field intensityand in particular electric current intensity which is then adjusted suchthat the flow resistance of the damping valve is adapted in real time.In this way it is allowed to specify, choose, or adjust, a great varietyof characteristic damper curves which the damper device thenautomatically holds. This allows automatic mode in which the riderbasically does not need to make any settings.

It is also a particular advantage of the method that agreeableresponsivity is provided since in normal state absent any disturbancesno field or only a particularly weak field of the field generatingdevice is applied. Thus no breakaway force or only a very low breakawayforce is required for triggering damping. The damper device is suppliedwith electric current only in the case of actual shocks. In shock- andvibration-free normal state the damper valve does not require anyelectric current. In this way very soft responsivity is obtained whichthe user perceives as agreeable.

Specifying a characteristic damper curve also allows to set a smoothtransition from the low-speed range to the high-speed range.

In all the configurations it is particularly preferred to reduce thefield intensity of the field generating device as soon as the obtained,current relative speed is lower than the immediately preceding relativespeed. Unlike prior art shock absorbers the shock absorber according tothe invention is not primarily controlled by way of ground recognitionbut the current state is recognized in real time and suitable damping isset in dependence on an obtained disturbance (of the basic state).Therefore the method according to the invention substantiallyautomatically suppresses for example the seesawing motion in sway pedalstroke.

Adjustment or in particular automatic selection of a characteristicdamper curve from multiple different characteristic damper curves ispossible and preferred. This allows to specify different characteristicdamper curves for example for various grounds to thus enable stillsofter or harder responsivity and the like. It is also possible to storedata and to automatically adapt the characteristic damper curve to theriding properties by way of stored parameters and the like. However,this does not change the fact that with every single shock the dampingforce of the shock absorber will still be controlled in real time.

Preferably the parameter is determined by way of at least one set ofparameters having at least one parameter, wherein at least one parameteris obtained from a group of parameters including, time data, timedifferences, position data, relative positions, absolute positions,relative speeds, absolute speeds, accelerations, relative accelerations,and the like, of at least the first and/or second components.Particularly preferably the parameter for the relative speed is obtainedfrom the set of parameters.

In all the configurations it is preferred for the characteristic dampercurve to substantially run through the origin of coordinates.Particularly preferably the characteristic damper curve runs preciselythrough the origin. Or else it is also possible that is runs quite closeto the origin. In the sense of this application, “substantially throughthe origin” is also understood to include deviations lying within 5% ofthe designed maximum values. For particularly soft responsivity adamping force close to zero is advantageous given a relative speed ofzero. It is preferred for the characteristic damper curve in theoperating state with the rider sitting on the bicycle to show, at zerospeed, a force less than 100 N and in particular less than 50 N.

In all the configurations the time interval between two successiveinstances of obtaining (what is the current) parameter is less than 30and in particular less than 20 ms. In particular is the time intervalless than 10 ms, preferably less than 5 ms or even less than 3 ms or 2ms. Short time intervals allow to very quickly capture any disturbancesoccurring.

Particularly preferably the regulating speed is faster than 50 ms and inparticular faster than 40 ms. Preferably the regulating speed is lessthan 30 and particularly preferably less than 20 ms. Particularlypreferably a regulating speed of less than 10 ms is achieved. Theregulating speed is presently understood to mean the period of time thatpasses for capturing by the sensor, evaluating the sensor signals, andsetting the field and building up the damping force. In particular isregulating speed understood to mean the time duration of one entirecycle of the control cycle.

Regulating speeds for example of 30, or 20 or 10 ms, have shown to besufficiently fast in the field of bicycles. Using rheological fluids andin particular magneto-rheological or else electro-rheological fluidsallows to achieve response times in the fluid of clearly less than 10ms. The shock absorber allows to keep the response times and regulatingspeeds even under full load. These response speeds are not possible ataffordable efforts for items fit for series production withconventional, mechanical valves. Known conventional bicycle dampers showresponse times of 250 ms or more. Moreover, changes to the flowresistance under full load require considerable energy in conventionalvalves. Unlike in conventional valves, a magneto-rheological dampingvalve does not involve reducing or enlarging a valve gap. Themagneto-rheological damping valve only requires application of amagnetic field with the energy used for generating the field independentof the flow rate of the medium in the damping valve.

In all the cases less than 20 ms and in particular less than 10 ms andpreferably less than 5 ms may pass between the relative motion of thetwo components and the adapted damper force resulting therefrom.

In all the configurations it is also possible to obtain through thesensor data or other data such as GPS sensors or the like, a parameterfor the surface-/ground-/roadway quality and, in dependence on theground conditions, to choose one of for example multiple predeterminedcharacteristic damper curves.

It is also possible to employ anticipatory models wherein the mostrecent measurement values are analyzed and for example a curve is drawnthrough the control points to obtain forecasts for the subsequentmeasurement values.

It is also particularly preferred for the characteristic damper curve tobe made steeper in the vicinity of an end position of the damper deviceto ensure a softer limit stop. In particular in the case of capturingposition data the vicinity of an end position can be readily determined.An augmentation of the field by means of the field generating deviceallows to set a higher end position damping.

It is also possible for the characteristic damper curve to be varied bymechanical or hydraulic means in the vicinity of an end position.

The shock absorber according to the invention is provided for an atleast partially muscle-powered bicycle, comprising at least one damperdevice disposed between first and second components for damping relativemotion. At least one control device and at least one memory device andat least one sensor device are provided also. The damper devicecomprises at least one controlled damping valve with at least one fieldgenerating device that is in particular configured as an electric coildevice. A field of the field generating device can act on afield-sensitive medium for influencing a damping force of the damperdevice by generating a field intensity of the field generating device.The control device and the sensor device are configured to periodicallyobtain in real time at least one parameter for current relative speedsof the first and second components relative to one another. The controldevice is configured to derive in real time a current field intensity tobe generated by means of the parameter from a characteristic dampercurve stored in the memory device. The control device and the fieldgenerating device are configured so as to set in real time the fieldintensity to be currently generated for setting in real time a dampingforce resulting from the predetermined characteristic damper curve atthe parameter obtained.

The shock absorber according to the invention also has many advantagessince it enables flexible control. At the same time, energy-savingoperation is enabled in which at all times the lowest possible but thehighest necessary field is applied on the damping valve. When employingan electric coil device as the field generating device the electriccurrent intensity can be kept the smallest possible at all times.

The measure of a current field intensity to be generated may for examplebe the electric current intensity or the voltage which is imposed on afield generating device for at least approximately generating thedesired current field intensity to be generated.

The parameter may be used for event recognition.

In another configuration of the invention the shock absorber accordingto the invention is provided for an at least partially muscle-poweredbicycle, comprising at least one damper device disposed between a firstand a second component for damping a relative motion. At least onecontrol device and at least one memory device and at least one sensordevice are provided also. The damper device comprises at least onecontrolled damping valve with at least one field generating device thatis in particular configured as an electric coil device. A field of thefield generating device can act on a field-sensitive medium forinfluencing a damping force of the damper device by generating a fieldintensity of the field generating device. The control device is equippedand configured for periodically controlling a control cycle. The controldevice and the sensor device are configured to periodically obtain inreal time at least one parameter for current relative speeds of thefirst and second components relative to one another. The control deviceis configured to derive in real time a current electric currentintensity to be set by means of the parameter from a characteristicdamper curve stored in the memory device. The control device and thefield generating device are configured to set in real time the electriccurrent intensity to be currently set for setting in real time withinthe control cycle a damping force resulting from the predeterminedcharacteristic damper curve at the parameter obtained.

Particularly preferably the damper device comprises a basic curve thatis predetermined by the mechanical configuration and by mechanicalvalves. Preferably the basic curve shows a gradient of the damping forcethat in negative relative speeds, thus in rebound, is steeper than isthe gradient of the damping force in positive relative speeds. Thus thebasic curve already allows a higher rebound damping.

In particular at least one mechanical valve is configured as amechanical one-way valve. It is possible for two different mechanicalvalves to be connected in parallel.

Preferably at least one mechanical valve and at least one damping duct,on which a field of the field generating device can be applied, areconnected in series. In all the configurations a maximum flowcross-section in the compression stage is preferably different from amaximum flow cross-section in the rebound stage. The maximum flowcross-section in the compression stage and/or in the rebound stage maybe limited through at least one mechanical one-way valve.

In all the configurations the control device captures, preferably atpredefined fixed or variable time intervals, the sensor signal, derivingtherefrom, by comparison against a characteristic damper curve orcontrol curve stored in a memory device, a control signal, thuscontrolling the field generating device so as to adjust the flowresistance by way of the damping valve according to the storedcharacteristic damper curve.

When capturing the parameters at known time intervals the currentrelative motion itself may be used as a magnitude and thus as aparameter for the current relative speed. Or else the current relativespeed may be computed by dividing the current relative motion by thetime interval. It is also possible to count pulses representing aspecific relative motion each. The number of pulses per unit time thenlikewise defines a relative speed and thus a parameter.

In another advantageous configuration the vehicle may for example belowered during riding. For example the suspension fork may be lowered orthe rear wheel shock absorber and/or the seat post can be intentionallycompressed. Such lowering is preferably not done immediately butdynamically, i.e. in dependence on the damper motion or the damperstroke. The rebound stage of the damper is locked within an extremelyshort time or at least full rebound is prohibited, in a desired position(stroke position) resulting from the compressing damper motion e.g. inbraking or riding through curves. For faster or further lowering thecompression stage can at the proper time be briefly set soft or softerand then in motion reversal the rebound stage can quickly be set hard orharder.

In compressing the compression stage must then (in particular quickly)be set softer so as to retain agreeable compressing.

In the same way the near field recognition system is conceivable incombination with the previously described shock absorber that switchesin real time for reducing the total time (recognition till force changeat the damper) e.g. in bicycles.

The same applies to speech recognition systems. Speech recognitionrequires comparatively long computing times. Only in combination with afast total system downstream of the speech recognition system(electronics, actor with field-sensitive, rheological medium) canresults be achieved that are good for the user. Speech recognition isalso conceivable by means of a mobile telephone or the like incommunication with the operating unit or the control unit.

In preferred embodiments the field generating device of the shockabsorber, absent any event or relative motion of the first and secondcomponents relative to one another, is substantially currentless or evenentirely currentless. In particular will electric energy not be requiredfor damping until an event occurs or relative motion of the first andsecond components to one another occurs. An event is the occurring of arelative motion of the first and the second components relative to oneanother. “Substantially currentless” in the sense of the presentapplication is understood to mean a state in which the field generatingdevice needs less than 10% and in particular less than 5% and preferablyless than 1% and particularly preferably less than 0.5% of the maximumelectric current intensity. “Entirely currentless” is understood to meana stage in which the field generating device requires absolutely noelectric current or in which only minor electric current intensities inthe region of less than 10 mA and in particular less than 1 mA andpreferably less than 500 μA are required.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin a shock absorber and method for operating a shock absorber inparticular for a bicycle, it is nevertheless not intended to be limitedto the details shown, since various modifications and structural changesmay be made therein without departing from the spirit of the inventionand within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 a schematic view of a bicycle equipped with a shock absorberaccording to the invention;

FIG. 2 a schematic view of the communication connections of the bicycleaccording to FIG. 1;

FIG. 3 a schematic sectional view of a shock absorber of the bicycleaccording to FIG. 1 with an electronic unit;

FIG. 4 a sectional side view of the shock absorber according to FIG. 3in an enlarged illustration in the compression stage;

FIG. 5 an enlarged sectional illustration of the shock absorber in therebound stage;

FIG. 6 the piston unit of the shock absorber according to FIG. 3;

FIG. 7 the cross section A-A from FIG. 6;

FIG. 8 a diagrammatic figure of the fan-like damping ducts; and

FIG. 9 an enlarged cross section of the piston unit;

FIG. 10 a first schematic illustration of a characteristic damper curvefor the shock absorber according to FIG. 3;

FIG. 11 a schematic illustration of the basic hydraulic curve of theshock absorber according to FIG. 3 and two different characteristicdamper curves;

FIG. 12 the time paths of the suspension travel, the piston speed, thedamping force, and the applied current intensity, for the shock absorberaccording to FIG. 3 during a jump; and

FIG. 13 another damper piston for the shock absorber according to FIG.3.

DESCRIPTION OF THE INVENTION

With reference to the enclosed figures an exemplary embodiment of abicycle 200 equipped with shock absorbers 100 will be discussed below.

FIG. 1 shows a schematic illustration of a bicycle 200 configured as amountain bike and comprising a frame 113 and a front wheel 111 and arear wheel 112. Both the front wheel 111 and the rear wheel 112 areequipped with spokes and may be provided with disk brakes. A gearshifting system serves to select the transmission ratio. Furthermore thebicycle 200 comprises a handlebar 116 and a saddle 117.

The front wheel 111 is provided with a shock absorber 100 configured asa suspension fork 114 and the rear wheel is provided with a shockabsorber 100 configured as a rear wheel damper 115. A central controldevice 60 is presently provided at the handlebar 116.

The central control device 60 may be employed as a suspension system,controlling both the suspension fork 114 and the rear wheel damper 115in synchrony. Control of the shock absorbers 100 and further bicyclecomponents may be provided in dependence on many different parametersand is also done by way of sensor data. Optionally the suspension and/ordamping characteristics of the seat post can be adjusted. It is possibleto also control by way of the central control device 60 the shiftingsystem for adjusting different transmission ratios.

Additionally each of the shock absorbers 100 comprises at least onecontrol device 46 at an electronic unit 50 provided to be exchangeable.The electronic units 50 comprise at least one battery unit 61. Thebattery units 61 may be exchanged together with the respectiveelectronic unit or separately. For example rechargeable battery unitsmay be provided which can be quickly removed from the shock absorbertogether with the electronic unit 50 for recharging the electronic unit.Also possible is energy supply by a central battery unit or byassistance or operation by a dynamo or the like.

Presently a control device 46 or a control unit is incorporated in theshock absorber wherein the control unit provides the basic functions.Operation then occurs via the electronic unit 50 or via the centralcontrol device 60. By means of the control device 60 or the controldevices 46 the damping properties of the suspension fork 114 and therear wheel shock absorber 115 can be set.

The central control device 60 is operated via an operating device 48. Itis possible for the control device 60 to have a display device 49 and/ormultiple operating knobs 51. It is also possible for the control deviceto be configured touch-sensitive or proximity-sensitive so as to allowoperation by way of touching dedicated buttons or the like.

The control device 60 may then also serve as a bicycle computer,displaying data such as the current speed, and the average speed and/orkilometers per day, per tour, per lap, and total. Also possible isdisplaying the current position, current altitude, or the route traveledor the route profile.

FIG. 2 shows a schematic illustration of the communication connectionsof the components involved. The central control device 60 may beconnected with the individual components either wire-bound or wirelessfor example through WLAN, Bluetooth, ANT+, GPRS, UMTS, LTE, or othertransmission standards. The connection shown in dotted lines with theinternet 53 is a wireless connection. The control device 60 may beconnected with the battery unit 61 or have its own energy supply.Furthermore the control device 60 may be connected with a sensor 47 ormultiple sensors 47. The graphic operating unit 57 or display unit mayalso have a wireless connection with the control unit 60. The shockabsorber 100 of the suspension fork 114 or the shock absorber 100 of therear wheel damper 115 may be connected wireless or wire-bound.Connection occurs through a network interface 54 which may be configuredas a radio network interface 55 or a cable connection 56.

In FIG. 2 the control cycle 12 is illustrated schematically which isstored in the memory device and stored or programmed in the controldevice 60 or the control devices 46. The control cycle 12 isperiodically performed in operation and in particular continuouslyperiodically. In step 52 e.g. the sensors 47 capture a current relativemotion or current relative speed of the first component relative to thesecond component. In step 52 a parameter is derived from the values ofthe sensor 47 or the sensors that is representative of the currentrelative speed. Thereafter in step 56 the pertaining damping force to beset is then derived from the obtained parameter 81 (see FIGS. 10, 11)taking into account the predetermined or selected characteristic dampercurve. A measure of the field intensity to be currently set is derivedtherefrom with which the damping force to be set is achieved at leastapproximately. The measure may be the field intensity itself or elseindicate the electric current intensity with which the damping force tobe set is obtained at least approximately. In the subsequent step 70 thefield intensity to be currently set is generated or the correspondingelectric current intensity is applied to the electric coil device as thefield generating device such that within one single cycle of the controlcycle 12 the damping force is generated which in the case of theselected or predetermined characteristic damper curve corresponds to thecurrent relative speed of the first component to the second component.Thereafter the next cycle starts and step 52 is once again performed.

FIG. 3 shows a simplistic cross-sectional view of a shock absorber 100which is presently employed for example in the rear wheel damper 115.

The shock absorber 100 comprises a damper device 1. The shock absorber100 is fastened, with the first end as the component 101 and the secondend as the component 102, to different frame parts for damping relativemotions.

In the damper housing 2 a damping piston unit 40 is provided whichcomprises a damping piston 5 as the damping valve 8 and a piston rod 6connected therewith. The damping piston 5 is provided with the dampingvalve 8 therein which presently comprises a field generating device 11and in particular an electric coil for generating a suitable fieldintensity. The magnetic field lines in the central region of the core 41run approximately perpendicular to the longitudinal extension of thepiston rod 6 and thus penetrate the damping ducts 20, 21 approximatelyperpendicular (see FIG. 4). FIG. 4 This causes the magneto-rheologicalfluid present in the damping ducts 20 and 21 to be effectivelyinfluenced so as to allow effective damping of the flow through thedamping valve 8. The shock absorber 100 comprises a first damper chamber3 and a second damper chamber 4 separated from one another by thedamping valve 8 configured as the piston 5. In other configurations anexternal damper valve 8 is possible which is disposed external of thedamper housing 2 and connected via supply lines.

The first damper chamber 4 is followed toward its end 102 by theequalizing piston 72 and thereafter by the equalizing space 71. Theequalizing space 71 is preferably filled with a gas and serves forequalizing the piston rod volume which in compressing enters into thewhole damper housing 2.

Magneto-rheological fluid 9 as the field-sensitive medium is present notonly in the damping valve 8 but in the two damping chambers 3 and 4 onthe whole.

The flow duct 7 between the first damper chamber 3 and the second damperchamber 4 extends, starting from the second damper chamber 4, firstlythrough the fan-type damping ducts 20 and 21 which at the other end leadinto the collection chamber 13 or collection chambers 13. Themagneto-rheological fluid collects there after exiting the damping ducts20, 21 before passing through the flow apertures 14, 15 into the firstdamping chamber 3. In compressing, i.e. in the compression stage, flowpasses through all of the flow apertures 14, 15. This means that themajor portion of the flow presently passes through the flow apertures 15and the one-way valves 17 automatically open at the flow apertures 15such that the magneto-rheological fluid can pass from the second damperchamber 4 into the first damper chamber 3.

In the compressed state illustrated the first damper chamber 3 isradially entirely surrounded by the second spring chamber 27 of thespring device 26. This allows a particularly compact structure.

In the case of complete rebound of the shock absorber 100 aspring-loaded plunger 75 causes pressure compensation between the firstspring chamber 26 and the second spring chamber 27.

The spring piston 37 is provided at the end of the damper housing 2.Disposed thereat is a holder 73 supporting a magnet 74. The magnet 74 ispart of a sensor 47. The sensor 47 comprises a magnetic potentiometerwhich captures a signal that is representative of the position of themagnet 74 and thus of the spring piston. This potentiometer 47 does notonly permit to determine a relative location but presently also permitsto determine the absolute stage of compression or rebound of the shockabsorber 100.

FIGS. 4 and 5 show partially enlarged details of the illustrationaccording to FIG. 3, FIG. 4 illustrating the case of the compressionstage and FIG. 5, the case of the rebound stage.

In the case of the compression stage illustrated in FIG. 4, i.e. incompressing, the magneto-rheological fluid 9 emerges from the seconddamper chamber 4 through the damping ducts 20, 21, entering the dampingpiston 5. The flow resistance through the damping ducts 20, 21 dependson the magnetic field of the field generating device 11 configured as acoil. After leaving the damping ducts 20, 21 the magneto-rheologicalfluid collects in the two collection chambers 13 (see FIGS. 9 and 13),thereafter passing through the flow apertures 15, which are permeable inthe case of the compression stage, with the one-way valves 17.

In the case of the rebound stage illustrated in FIG. 5 themagneto-rheological fluid flows from the side 22, the side of the pistonrod 6, toward the damping piston 5. The one-way valves 17 at the flowapertures 15 close automatically such that only the flow apertures 14configured for the through holes 16 in the piston rod 6 remain forputting the magneto-rheological fluid into the damping piston 5. Whenthe magneto-rheological fluid 9 has entered through the through hole 16in the collection chamber 13 or into the collection chambers 13, themagneto-rheological fluid evenly flows through all the fan-type dampingducts 20, 21 until the magneto-rheological fluid exits from the dampingpiston 5 at the other flow side 23. It can also be clearly seen in FIG.5 that the damping piston 5 comprises a coil as the field generatingdevice 11, a core 41 of a magnetically conducting material and a ringconductor 36. Furthermore an insulating material 42 may be provided.

The collection chamber 13 enables an efficient series connection of theone-way valves 17, which are in particular configured as shim valves,with the damping ducts 20, 21. The collection chamber 13 serves to avoidin particular inadmissibly high loads on the fan walls 19 due todifferent pressures in the damper ducts 20, 21. Operating pressures of30 bars, 50 bars and more can occur which in the case of different loadson both sides of a fan wall 19 may lead to destruction of the thin fanwalls 19.

FIG. 6 shows a side view of the damping piston unit 40 with the dampingpiston 5 and the piston rod 6 from the end of which the cable 38protrudes. The length 31 of the damping ducts 20, 21 is exemplarilyshown. In this illustration one can clearly see the flow aperture 14configured as a through hole 16 with the inclined inlet 25 following,which provides for an automatically increasing end position damping.When the shock absorber 100 rebounds nearly entirely, then the springpiston 37 firstly slides across the flow aperture 16 and thereafteracross the inlet 25, so as to have the flow cross-section continuallydecreasing and thus the damping force automatically increasing.

FIG. 7 shows the cross-section A-A in FIG. 6. The core 41 is surroundedby the field generating device 11 configured as a coil. Damping ducts 20and 21 are disposed in the core. The core and the coil are radiallysurrounded by ring conductors 36.

FIG. 8 shows an enlarged illustration of the damping ducts 20, 21provided in the core 41. The fan-type damping ducts 20, 21 are separatedfrom one another by a fan wall 19. A wall thickness 29 of the fan wall19 is less than a height 30 of a damping duct 20 or 21. Thecross-sectional area 33 of the fan wall 19 is again considerably smallerthan is the cross-sectional area 34 or 35 of the damping ducts 20 or 21.In the illustrated example the wall thickness 29 of the fan wall 19 isapproximately 0.3 to 0.6 mm. The clear height 30 of the damping ducts 20or 21 is larger, being 0.5 mm to 0.9 mm.

Values for damping ducts 20, 21 of a rear wheel damper 115 aretypically, without being limited thereto, duct lengths 31 betweenapproximately 10 and 30 mm, duct widths between approximately 5 and 20mm, and duct heights between approximately 0.2 and 1.5 mm. Up to tendamping ducts 20, 21 may be present which may in turn be combined toform one or more groups. Within such a group the damping ducts 20, 21are separated from one another by fan walls 19 whose wall thicknessesare typically between 0.2 and 1 mm.

The clear flow cross-section, being the sum total of all the dampingducts 20, 21, largely depends on the duct shape, the fluid employed, thepiston surface, and the desired range of force. The clear flowcross-section typically lies in the range between 10 and 200 squaremillimeters.

FIG. 10 shows a characteristic damper curve 10 of the shock absorber 100according to FIG. 3 with the damping valve 8 in a force-speed diagram.The low-speed range 91 and the high-speed range 92 are connected with aradius 93 by way of a gentle rounding. The characteristic damper curve10 is presently asymmetric. Although the characteristic damper curve 10basically shows similar curve paths for the compression and reboundstages, the gradient in the rebound stage is specified to be steeperthan in the compression stage.

The characteristic damper curve 10 is set electrically in real time atall times, taking into account the hydraulic basic damping, such that ineach instance of a shock or event or each disturbance 85 a suitabledamping force is set still during the shock 85 or the disturbance.

The gradient 94 of the characteristic damper curve 10 in low-speed range91 can be well approximated both for the compression stage and therebound stage, by way of a straight line showing a substantially lineargradient 94 or 98. The predetermined characteristic damper curve 10 runsthrough the origin of coordinates such that in the case of a relativespeed of the damper piston 5 of zero, there is no damping force. Thisallows a very soft and agreeable responsivity.

In the high-speed range 92 the gradients 95 and 99 are presently alsospecified as substantially linear. A curved intermediate section 93 mayextend in-between so as to avoid break points 96. Also or one linearintermediate section 93 or multiple linear or slightly curvedintermediate sections 93 may be provided to approximate a curved path.

Furthermore an arrow 97 is inserted indicating the effect of a magneticfield having different strengths. Given a higher magnetic field strengththe characteristic damper curve shifts upwardly while with a weakermagnetic field it shifts downwardly.

A characteristic damper curve with no intermediate section 93 providedis drawn in a dotted line so as to result in more or less noticeablebreak points at the points 96.

The gradients 94 and 98 in the low-speed region 91 and the gradients 95and 99 in the high-speed regions 92 are modifiable and adaptable to thecurrent wishes and conditions, as is the entire characteristic dampercurve 10. In this way, as a different ground is recognized, a differentcharacteristic damper curve can be selected automatically, specifyingsofter or else harder damping. Independently of the selectedcharacteristic damper curve, each and every shock is dampened in realtime at all times.

The gradients 95 and 99 in the respective high-speed regions 92 areagain specified and can be changed as needed. The power supply for thecontrol device and the electric coil as the field generating device 11may also be provided by a battery, an accumulator, a generator, dynamo,or in particular a hub dynamo.

FIG. 11 illustrates the basic curve 62 and two different characteristicdamper curves 10 and 90. It shows the damping force over the relativespeed of the components 101 and 102 to one another.

The basic curve 62 represents the hydraulic properties of the shockabsorber 100 where no magnetic field is applied. The gradients of thebasic curve in the compression stage and in the rebound stage differ bythe one-way valves 17 and in the rebound stage they are steeper than inthe compression stage.

The characteristic damper curves 10 and 90 are asymmetric in FIG. 11.The characteristic damper curves 10 and 90 represent the resultingdamping forces over the relative speed and they are composed of thedamping force of the basic curve 62 and the magnetically generateddamping force. This means that in the case of a specific compressing orrebounding speed, a damping force lower than the damping force of thebasic curve 62 cannot be set. The basic curve 62 must be taken intoaccount in designing. Weaker damping is not possible due to theprinciple. On the other hand, given a particularly small differencebetween a characteristic damper curve 10 and the basic curve 62, theelectric energy required is particularly low such that a certainadaptation of the basic curve 62 to the softest characteristic dampercurve provided is useful. The softest characteristic damper curveprovided may e.g. be the characteristic damper curve 10.

A basic curve 62 with “useful” properties ensures reasonable emergencyrunning properties in case that the power supply ceases to providesufficient energy. Also possible and preferred is a mechanicallyadjustable emergency valve to provide adjustable emergency runningproperties.

The gradients in the compression stage and the rebound stage aredifferent. In the rebound stage the gradient 96 is approximately linearon the whole. In the rebound stage there is virtually no differentiationbetween the low-speed region 91 and the high-speed region 92.

In the compression stage, however, the low-speed region 91 and thehigh-speed region 92 presently show different gradients 94 and 95 in thecase of both the characteristic damper curves 10 and 90 drawn in.

The control device 46 periodically scans the sensor 47 at short,equidistant time intervals of e.g. 1 ms, 2 ms or 5 ms. The controldevice 46 computes from the signals a parameter 81 for the relativespeed 82. It is possible for the control device to obtain from thesensor signals a relative speed 82 to be employed as the parameter 81.In the simplest of cases the sensor 47 directly obtains the associatedrelative speed. In another simple case the sensor 47 or the controldevice 46 obtains from the sensor signals a change in path or positionof the components 101 and 102 relative to one another. With the timeinterval between two measurements known, a relative speed 82 and thus aparameter 81 can be derived therefrom. If the time interval between twomeasurements is substantially constant, a change in position or relativemotion may be directly used as the parameter 81.

It is also possible to obtain from values from acceleration sensors orfrom a set of parameters of multiple different sensor values, aparameter 81 which is representative of the current relative speed 82.One embodiment provides for the data from acceleration sensors and/ordisplacement sensors to be coupled such that on the one hand, quickreaction is possible to fast changes due to jumps or roughness of road,and on the other hand, precise positioning and speed sensing is achievedin slower actions.

With the parameter 81 thus obtained, the pertaining damping force 84 or84′ is obtained by means of the characteristic damper curve 10 or e.g.90 stored in a memory device. The associated magnetic field and thepertaining electric current intensity of the coil 11 are derived andadjusted in real time. This means that a cycle is completed within 20 msand as a rule within 10 ms. Measurements may be taken more frequently,e.g. at time intervals of 5 ms or even at time intervals of 1 or 2 ms orfaster still. The control device processes the sensor signals received,generating by means of the coil 11 a magnetic field of a suitable fieldintensity for generating the damping force pertaining to the parameter81. The magnetic field acts within the provided cycle time of e.g. 10ms, adjusting the desired damping force 84.

If the relative speed 82 has changed after another measuring period, acorrespondingly different magnetic field is generated such that thecontrol cycle consisting of sensor 47, control device 46 and dampingvalve 8 as the actor keeps the desired response time, adapting thesystem in real time.

Measurements have shown that in bicycle dampers, response and cycletimes of 10 or 20 ms are entirely sufficient for adjusting damping inreal time.

This is also shown in the data of an actually measured and dampened jumpas illustrated in FIG. 12.

FIG. 12 shows, one above the other, in a number of separate diagramsover time the measurement and control data during a jump performed witha bicycle.

The topmost diagram illustrates the suspension travel in millimetersover time in seconds with the entire time scale only showing 2 seconds.Beneath, the relative speed, the damping force, and the electric currentintensity are illustrated accordingly over the same time interval.

Initially the shock absorber 100 is located inside the SAG position andis compressed about 12 mm. During the jump as the event 85 the shockabsorber 100 rebounds such that the damping piston 5 is in nearlycomplete rebound at approximately 0.75 seconds.

After touchdown on the ground the rear wheel begins compressing,obtaining a maximum compressing and thus relative speed 67 in thecompression stage which occurs at approximately 0.8 seconds andpresently achieves values above 0.4 m/s. At the same time the maximumdamping force 68 of presently approximately 500 N is generated at themaximum of the electric current intensity 69 in the compression stage.

A very short time later the maximum compression 66 is reached at thetime 64 where the relative speed 67 reaches zero. Accordingly thecontrol device reduces the electric current intensity to zero such thatthe damping force is zero.

Thereafter the rebound stage damping follows while the shock absorber100 rebounds once again. At the same time the electric current intensityincreases accordingly for adjusting a damping force which corresponds tothe relative speed 67 given the characteristic damper curve set.

The maximum relative speed 77 in the rebound stage will occur at thetime 65 which presently results in a maximum electric current intensity79 for generating a maximum damping force 78 of approximately 600 N.

The duration of the jump results from the duration 58 of the compressionstage of approximately 0.2 seconds and the duration 59 of the reboundstage of approximately 0.5 seconds, plus the preceding rebound phase.

It immediately follows from the times indicated that a regulating speedof 250 ms is not sufficient. In order to operate at real time, thesystem must respond within at least 50 ms and better within 20 ms whichis presently ensured.

The regulating speed including capturing a sensor signal, deriving aparameter, adjusting the current intensity, and adjusting the dampingforce 84, is presently less than 10 ms. Thus the control cycle 12 or thecontrol loop is passed through about 200 times within the time periodillustrated in FIG. 12.

FIG. 13 shows another damper piston 5 for the shock absorber 100according to FIG. 3. Each of the ends of the damper piston 5 is providedwith at least one collection chamber 13. This allows to provide each ofthe ends of the damper piston with additional flow apertures 14 as flowvalves 43 provided in series with a damping duct 20. It is also possibleto provide two or more damping ducts 20 and 21.

Due to providing the at least one damping duct 20 between mechanicalflow apertures 14 or mechanical flow valves 43, different damping forcescan be chosen in the compression and rebound stages. The flow apertures14 may be configured partially as through holes 16 and partially asone-way valve 17. In this way different damping forces of the basiccurve 62 may be specified in each flow direction independently of oneanother.

The flow valves 43 in particular configured as one-way valves 17 may beadjustable by means of adjusting means 44 such as screws or rotaryelements for setting the flow resistance in relation to the direction.For example each of the ends may be provided with a rotary ring as theadjusting means 44 which, in relation to the angle of rotation, closespart or all of one, two, or more of the flow apertures provided over thecircumference such that the maximum flow cross-sections available in oneor the other of the flow directions 22 or 23 can be set accordingly.

In this way the basic curve 62 of the shock absorber 100 can be adaptedas desired both in the rebound stage and in the compression stage. Forexample an adaptation of the basic curve 62 of the shock absorber 100 tothe type of frame may be provided. Depending on the frame geometry andthe frame size and the mounting position, preadjustment may be done soas to provide for basic adaptation of the basic curve 62 to theinstallation conditions.

The basic curve 62 is then preferably set to the mounting situationprovided such that it corresponds approximately to the characteristicdamper curve 10 having the softest damping provided. If only softdamping is desired or set, then no electric energy at all will berequired. The electric coil must be energized only at those times whenstronger damping is required. This measure allows to once againconsiderably reduce electric current consumption.

In all the operating modes of the shock absorber 100 at least onedisplacement sensor is employed preferably as the sensor device 47. Thesensor device 47 is preferably read e.g. at a frequency of 2 kHz and aresolution of 12 bits. In theory, given a stroke of a rear wheel damper115 of 50 mm once in every 0.5 ms, the relative motion can be determinedat an accuracy of 12 μm. Unlike thereto, a suspension fork 114 shows astroke of e.g. 150 mm, such that under the same conditions a relativemotion can be determined at an accuracy of 36 μm.

The data captured by means of the sensor device 47 preferably passthrough a low-pass filter and are used for computing the speed wherein aspecific damping force is computed by way of the current speed,direction, and the preset characteristic damper curve. This computingoperation is repeated e.g. at 500 Hz such that a new force specificationis generated once in every 2 ms. An electric current to be set isobtained from the damping force based on the known conjunction ofdamping force and field intensity required therefor and in turn theelectric current intensity required therefor. In particular a dedicatedelectric current regulator sets the respective electric current at theelectric coil device at the shock absorber by way of this specifiedforce such that the resulting damping force is traced sufficiently fastand substantially corresponds to the specification.

The conversion to a digital signal of a relative motion measured byanalog meter and the subsequent computing of the specified electriccurrent or the electric current to be set requires hardly any resources,and using a state-of-the-art microcontroller it can be done in a matterof mere microseconds. The electric current regulator provides adequatelyfast response of the electric coil device such that, notwithstandinginductivity and eddy currents, an electric current jump from 0 to 100%is possible in very few milliseconds.

What is advantageous for the responsivity of the electric currentregulator is, the low-pass filter and computation of the relative speedwhere presently a compromise must be found between fast response andfilter effect. The filter parameters may be dynamically adapted to theprevailing situation.

Given fast filtering, a relative motion or change in position will inthe worst case scenario be recognized in the subsequent regulating pulseafter 2 ms and will then be processed within a few microseconds. Theelectric current regulator will virtually instantly work towardimplementing the new specification of electric current. The dampingforce acts at some delay following the specification of electriccurrent. The response time of the magneto-rheological fluid (MRF) isless than 1 ms. The rigidity of the system is again of minor importance.Depending on the concrete structure the new nominal value of the dampingforce is obtained within a few milliseconds. Jump response times of lessthan 10 ms are readily feasible with the system and have been verifiedsuccessfully in the past. Depending on the requirements and availablemanufacturing costs, faster components may be employed which allow jumpresponse times in the region of one-digit milliseconds.

Regulation (closed-loop control) may also be based on fuzzy logic and/orlearning.

Two or more dampers may be linked electrically to form one system. Inthis case e.g. relevant data are transmitted from a first damper to asecond damper in real time such that it can better adapt to the event.For example the damper in the suspension fork can transmit theinformation to the rear wheel damper such that the latter can anticipatee.g. a severe shock. The entire system will thus be more efficient.Also/or a hydraulic link of two or more dampers is possible (open orclosed hydraulic system).

The damper device may comprise two or more controllable damping valveshaving one (or multiple) field generating device(s). These may beattached external of the components movable relative to one another. Itis also possible to provide at least one permanent magnet whichgenerates a static magnetic field. The strength of the magnetic fieldeffectively acting in the damping valve can then be modulated in realtime by the magnetic field generated by the electric coil as the fieldgenerating device.

On the whole the invention provides an advantageous shock absorber whichcan be applied both as a rear wheel shock absorber and in a suspensionfork. Different basic damping in the compression and/or rebound stagesis enabled in a simple way. The difference depends on the orientation ofthe one-way valves in the flow apertures. In this way a flexible andcomprehensive adaptation to many different requirements can be ensured.Controlling takes place in real time so as to provide prompt andimmediate response to all the occurring events, disturbances, shocks orobstacles.

List of reference numerals: 1 damper device 2 damper housing 3 firstdamper chamber 4 second damper chamber 5 damping piston 6 piston rod 7flow duct 8 damping valve 9 field-sensitive medium 10 characteristicdamper curve 11 field generating device, coil 12 control cycle 13collection chamber 14 flow aperture 15 flow aperture 16 through hole 17one-way valve 18 valve opening 19 fan wall 20 damping duct 21 dampingduct 22 one flow side 23 other flow side 24 flow direction 25 inlet 26spring device 27 first spring chamber 28 second spring chamber 29 wallthickness 30 clear extension 31 length 32 width 33 cross-sectional area34 cross-sectional area 35 cross-sectional area 36 ring conductor 37spring piston 38 cable 39 end position 40 damping piston unit 41 core 42insulating material 43 flow valve 44 adjusting means 45 memory device 46control device 47 sensor 48 operating device 49 display 50 electronicunit 51 control knob 52 step 53 internet 54 network interface 55 radionetwork interface 56 step 57 graphical operating unit 58 durationcompression stage 59 duration rebound stage 60 control device 61 batteryunit 62 basic curve 63 time 64 time 65 time 66 max. compression 67 max.relative speed 68 max. damping force 69 max. electric current intensity70 step 71 equalizing space 72 equalizing piston 73 holder 74 magnet 75plunger 77 max. relative speed 78 max. damping force 79 max. electriccurrent intensity 80 relative motion 81 parameter 82 relative speed 83field intensity to be set 84 damping force 85 event 86 relative position87 time interval 90 characteristic damper curve 91 low-speed range 92high-speed range 93 transition region 94 gradient 95 gradient 96 breakpoint 97 arrow 98 gradient 99 gradient 100 shock absorber 101 componentfirst end 102 component second end 111 front wheel 112 rear wheel 113frame 114 suspension fork 115 rear wheel damper 116 handlebar 117 saddle200 bicycle

The invention claimed is:
 1. A method of operating a shock absorber fora bicycle, the shock absorber having a first component, a secondcomponent, and a damper device connecting the first and secondcomponents to one another, and wherein a relative motion between thefirst and second components is damped, the method which comprises:providing the damper device with at last one controllable damping valvehaving at least one field generating device configured to influence afield-sensitive medium for influencing a damping force of the damperdevice by generating a field intensity of the field generating device;providing a characteristic damper curve; periodically obtaining, in realtime, a parameter for a current relative speed between the first andsecond components; deriving by way of the parameter a measure for afield intensity to be currently set from the characteristic damper curvein real time; driving the field generating device to be current-less inan absence of an event and energizing the field generating device withelectric energy for damping only as an event occurs; and when an eventoccurs, generating with the field generating device the field intensityto be currently set in real time for setting in real time a dampingforce that results from the characteristic damper curve at the parameterfor the current relative speed; wherein a closed-loop update speed isfaster than 40 ms, so that a regulating speed including a period of timerequired for obtaining the parameter, evaluating resultant sensorsignals, and setting the field and building up the damping force isfaster than 40 ms.
 2. The method according to claim 1, wherein thecharacteristic damper curve defines a relationship between the dampingforce and the relative speed, thus determining the relationship betweenthe field intensity of the field generating device and the dampingforce.
 3. The method according to claim 1, wherein the damping forceincreases with an increase in the relative speed and wherein the dampingforce increases with an increase in the field intensity of the fieldgenerating device.
 4. The method according to claim 1, wherein thecharacteristic damper curve approximates a straight line with apredetermined low-speed gradient in a range of relatively low positiveand/or negative relative speeds.
 5. The method according to claim 4,wherein the characteristic damper curve approximates a straight linewith a predetermined high-speed gradient in a range of high positiveand/or negative relative speeds.
 6. The method according to claim 5,wherein the characteristic damper curve includes a curved transitionregion in a range of a medium positive and/or negative relative speed.7. The method according to claim 1, wherein the characteristic dampercurve is adjustable or selected.
 8. The method according to claim 1,which comprises reducing the field intensity of the field generatingdevice when the relative speed is lower than an immediately precedingrelative speed.
 9. The method according to claim 1, wherein the step ofdetermining the parameter comprises obtaining at least one set ofparameters having at least one parameter from a group of parametersconsisting of time data, time differences, positions, relativepositions, absolute positions, relative speeds, accelerations, relativeaccelerations, of at least one of the first or second components. 10.The method according to claim 1, which comprises obtaining the parameterfor the relative speed from the set of parameters.
 11. The methodaccording to claim 1, wherein the characteristic damper curvesubstantially runs through an origin of coordinates.
 12. The methodaccording to claim 1, wherein a time interval between two mutuallysuccessive instances of obtaining the parameter is less than 20 ms. 13.The method according to claim 1, wherein a time interval between twomutually successive instances of obtaining the parameter is less than 20ms.
 14. The method according to claim 1, which comprises setting a timedifference between a relative motion and a correspondingly adapteddamping force resulting therefrom to less than 20 ms.
 15. The methodaccording to claim 1, which comprises storing parameters andautomatically selecting the characteristic damper curve by way of storedparameters.
 16. The method according to claim 1, which comprisesacquiring information regarding a ground quality and selecting acharacteristic damper curve in dependence thereon.
 17. The methodaccording to claim 1, which comprises operating in an adaptation modewherein data are stored and the characteristic damper curve is modifiedby way of stored data.
 18. The method according to claim 1, whichcomprises setting the characteristic damper curve relatively steeper ina vicinity of an end position of the damper device.
 19. The methodaccording to claim 18, which comprises automatically increasing asteepness of the characteristic damper curve in the vicinity of an endposition by mechanical means.
 20. The method according to claim 1, whichcomprises suppressing seesawing by substantially suppressing periodicalrelative motions.
 21. The method according to claim 1, which comprisesproviding the damper device with at least one mechanical valve and atleast one damping duct connected in series and driving the fieldgenerating device to selectively subject the field-sensitive medium inthe at least one damping duct to the field.
 22. The method according toclaim 1, which comprises providing the damping device with a maximumflow cross-section in a compression stage that is different from amaximum flow cross-section in a rebound stage.
 23. The method accordingto claim 1, which comprises selecting a characteristic damper curve froma variety of characteristic damper curves.